Should we be more worried about global warming or the next ice age?

We have been hearing a lot about climate change and global warming. What about the next ice age? If global warming is real and all ice in the poles melt, sea levels could rise by about 200 feet. If, on the other hand, the next ice age happens, Pennsylvania could be under hundreds of feet of ice. Should we be more concerned about the global warming or the next ice age?

Global warming proponents cite records on carbon dioxide from the National Oceanic and Atmospheric Administration that date back to 1958 and ice core measurements since 1750. Carbon dioxide is a greenhouse gas that traps heat energy in the atmosphere and reduces heat that radiates to outer space, thereby increasing the temperature of the atmosphere. A significant fraction of carbon dioxide comes from burning fossil fuels, and automobiles contribute largely to this emission. Automobiles emit other greenhouses gases too, although in smaller concentrations, that can contribute to global warming.

Carbon dioxide concentration in the atmosphere was about 270 parts per million in 1750, increasing to about 310 ppm in 1958, and has progressively increased to more than 400 ppm today with current annual increase of about 1.5 to 2 ppm. What does one ppm mean in terms of actual numbers? One ppm by volume carbon dioxide in air translates to approximately 1.5 ppm by weight. Calculations show that we have about 1018 kilograms air in our atmosphere (seen as the “thin blue line” around our planet in photographs taken from space), which is a million trillion kg air. This means that we are emitting one trillion kg carbon dioxide into our atmosphere every year. A significant fraction of this emission comes from our automobiles.

On the other hand, climate scientists point out that during earth’s age of 4.5 billion years, there have been five big ice ages, some of which lasted hundreds of millions of years. Within these big ice ages, there were smaller ice periods called glacials and warmer periods called interglacials. Apparently, we are in an interglacial, and scientists suggest that this warm period could last about a hundred thousand years at the current warming trends.

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If the next global cooling is that far ahead, we may need to be concerned immediately about warming and not cooling. In order to reduce or at least prevent increase current carbon dioxide concentrations, our annual emission must be reduced by a magnitude of the order of a trillion kg. We need to look at other forms of energy than fossil fuels to run our automobiles and heat our homes. One solution is to look at electricity as a fuel. It is important, however, that the electricity that we use is produced from non-fossil sources; otherwise we are only changing the location of production of emissions from the point of use to the power plant. Solar, wind and hydroelectric power plants offer possible pathways. Nuclear energy is also a possible solution if we can deal with the waste and the safety of their operation.

OLLI at Penn State — open to adults who love to learn — offers more than 140 courses this semester. Suresh Iyer will lead a course on “Vehicle Emissions and Our Environment”in March. To receive a free catalog for the current spring semester, call OLLI at Penn State at 867-4278 or visit olli.psu.edu.

Suresh Iyer is a senior research associate at the Larson Transportation Institute at Penn State.